The finish of the truck race and then the initial aftermath couldn’t have been more exciting.

Two young drivers battled for the lead with one getting dumped—if Chase Elliott had turned his wheel instead of just driving straight through the corner, he would have had a much better argument—and several drivers were pointing fingers and beating and banging afterward.

No one was going to get physically hurt Sunday at Canadian Tire Motorsport Park, just some hurt feelings and some damage to cars as well as in the standings.

But then the stupidest move of the season came, and it wasn’t by a driver. Kelly Heaphy, the girlfriend of driver Mike Skeen, slapped Max Papis in the face.

For a sport that still gets mocked as not a professional sport, this was an embarrassing moment. This was about as trashy as the sport could appear. This wasn’t about showing emotion. It was about showing immaturity.

Drivers and crews can push and shove. But no one should be punching anyone in the garage, and certainly WAGS do not slap drivers.

NASCAR needs to give Heaphy a lengthy suspension, probably an indefinite suspension for as long as Skeen attempts 17 races (half a season). The team needs to be fined as a deterrent for those girlfriends of other drivers who might want to take matters into their own hands.

If two drivers get out of their car and start shoving each other in the heat of the moment after an accident or fender-banging, that’s one thing. If crew members try to separate them and get caught up in it, OK.

But the NASCAR garage can’t be so lawless that people can go slapping anyone they see fit.

When Richard Childress punched Kyle Busch after a truck race at Kansas last year, he should have been suspended. He got off with a $150,000 fine.

That incident, much like the one Sunday, was a premeditated attack. Heaphy walked up there with one thing in mind, to slap Papis. This wasn’t heat of the moment. She wasn’t in a racecar. She was apparently mad at something Papis said.

Papis initially said the slap dislocated his jaw, although he tweeted Tuesday that it actually was a sprain.

So what appeared to many as a funny little episode actually caused a somewhat significant injury.

It is real easy just to look at this and laugh and say this was a shocking incident, just a little Jerry Springer that spiced things up—something that proved NASCAR brings out raw emotion.

But there needs to be some sort of decorum in the garage. It just can’t be a place where because someone is mad, they can wallop someone.

Like it or not, NASCAR needs its corporate sponsors. It can’t have just anyone in the garage fighting just when they’re upset over a late-race incident or someone says something mean about their family. That’s something people get arrested over.

The last thing NASCAR wants is for people to be arrested in the garage. It wants the garage treated like a hockey rink, where for the most part, the sanctioning body has jurisdiction. That way it can be lenient when the heat of competition boils over.

When the Jeff Gordon and Clint Bowyer crews were pushing and shoving at Phoenix last year, cops told crewmen that if they picked up tires to use in the fight, they would be arrested on the spot. The crewmen listened and NASCAR was fairly lenient with the penalties.

But this slap is one place where it can’t be lenient. This is one time NASCAR has to put its foot down, has to do more than say this was unacceptable.

The code needs to remain that drivers handle things among themselves. They are the ones risking their lives every second on the track. They’re the ones who truly know what happened.

Instead, now a NASCAR driver looks like he can’t stick up for himself and another is being ridiculed for getting slapped.

There are no winners here, even in the theory of all publicity is good publicity. For a series that likes to promote “tough trucks” and “tough drivers,” it can’t add “out-of-control girlfriends.”

NASCAR has the Chase for the Sprint Cup field about to be decided—and while a great battle between two future Chase participants in a truck race is a great complement to the Cup drama, the fact that this slap has overshadowed other news is a downright shame.

This isn’t to say drivers and their teams can’t show emotion. But there is a line, and it was crossed once Heaphy swung her hand.